• Chronological Sequence of Evaporator Operations:
• In dairy and food engineering, the operational procedure for a falling film or forced circulation evaporator follows a rigorous thermodynamic sequence:

• Step 1: Preheating the feed solution: Raw liquid feed is preheated close to the boiling temperature using regenerate heat exchangers to conserve energy.
• Step 5: Heating the feed solution to its boiling point: The liquid is brought to its saturation boiling point within the evaporation chamber/calandria tubes.
• Step 2: Vaporization of the solvent from the feed solution: Latent heat of vaporization causes rapid water evaporation, concentrating the non-volatile milk solutes.
• Step 3: Condensation of the vaporized solvent to produce distillate: Separated water vapor passes to a condenser (or mechanical vapor recompressor, MVR) to produce condensate.
• Step 4: Removal of concentrated solution or residue: The concentrated product (condensed milk/dairy syrup) is continuously discharged through the bottom extraction pump.
  • Conclusion: The correct chronological sequence is 1 - 5 - 2 - 3 - 4 (Option 1).

• Mass Transport through Food Packaging Polymers:
• Pressure dependence: Gas permeability ($P = D \times S$) through polymeric barriers increases as pressure differential increases due to higher gas solubility and matrix plasticization.
• Temperature dependence: Gas diffusion coefficient increases exponentially with temperature according to Arrhenius kinetics ($D = D_0 e^{-E_d/RT}$).
• Polymer polarity: Non-polar hydrocarbon polymers (Polyethylene - LDPE/HDPE, Polypropylene) lack hydrophilic groups, exhibiting excellent water vapor barrier properties (low WVTR).
• Statement C is false: Polar polymers (EVOH, cellophane, polyamide) absorb moisture and possess poor water barrier properties.
• Conclusion: A, B, D only (Option 2).

Correct option: (2) A.B,D only

• Match Instrumentation Transducers with Working Principles:
• Strain Gauge $\longrightarrow$ (I) Mechanical deformation to electrical signal: Piezoresistive sensor whose electrical resistance alters proportionally to mechanical strain ($R \propto \Delta L$).
• Thermocouple $\longrightarrow$ (II) Temperature measurement via Seebeck effect: Generates an electromotive force (EMF) at the junction of two dissimilar metallic conductors proportional to temperature difference.
• LVDT (Linear Variable Differential Transformer) $\longrightarrow$ (III) Precision linear displacement: Inductive transducer converting core linear mechanical position into differential secondary AC voltage with extreme linearity.
• Piezoelectric Transducer $\longrightarrow$ (IV) Electrical charge under mechanical pressure/vibration: Asymmetric crystal (quartz, PZT) generating electric surface charge in response to applied dynamic stress.
• Conclusion: A-I, B-II, C-III, D-IV (Option 2).

Correct option: (2) AA,B-I,C-I,D-V.